DESCRIPTION: (Applicant's Abstract) To date no randomized controlled trials of syringe exchange have taken place. This research is both an efficacy study and a feasibility study design of a two group randomized clinical trial in which current and former injection drug users are assigned to: (a) being able to use a syringe exchange, or (b) not having access to the syringe exchange and being encouraged to use legal pharmacy sales instead. All subjects are followed up every six months and information is collected with Risk Behavior Assessment, a supplementary questionnaire concerning needle use and procurement, locator information, urine testing for amphetamines, cocaine metabolites, and morphine, and serological testing for markers of Hepatitis B Virus. Markers of Human Immunodeficiency Virus will also be monitored. There will be a Data Safety and Monitoring Board who will be overseeing the progress of the research and will have oversight over the ethical issues involved in this research.